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House burned down

Thank goodness all your people are ok. Things can be replaced, family can not. Your build looked good, it’s going to be difficult to nail down what went wrong. I’m still skeptical of Victrons use of mega fuses, I have a class T fuse close to the positive of each battery.

Agree with this.

And ABYA recommends battery fuses be within 7 " of the battery terminal.
 
If a fuse arcs, how does this spread to a fire?
I've seen videos of fuses blasting plasma. When in a metal enclosure, the test dummy fares better.
Maybe the fuse holders? Or what was behind it if it's wasn't steel sheet or some fire resistant backer material.
 
WOW! Just WOW!

Well, the fuse worked…
But the power was high enough to arc over the melted fuse. And that continued long enough to set a fire.
I’d contact the fuse maker. Too short a section that actually melts away from the fuse tabs.
 
I sympathize with you. Your build looked to be a professional build looking at your previous post.

When fuses blow, then there is a root cause for the fuse to blow as I found out with my 93 Dodge Ram truck when one of the fusible links blew and the mechanic changed out the link without determining the root cause and it blew again which left me stranded in a very precarious situation.

I know this is hard for you but for all of us in this forum that have their family at risk, the more that we can find out about this tragic loss the safer we will all fill. I have my 110kwhr LFP pack in the cellar of my home. If that caught on fire, then the whole house would go.

I have my Cells divided into two parts with two class t 200 amp fuses to protect the Cells. There are 128 -280 amp Cells. I did not put my Cells in a metal enclosure or compress them. They are on a nice piece of wood. This has really got me thinking about what I can do to protect myself further.

I am thinking about maybe fire blankets or some sort of a fire alarm that can be heard while sleeping two floors above the cellar.

Any suggestions would be appreciated. The simpler the better.
 

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Agree with this.

And ABYA recommends battery fuses be within 7 " of the battery terminal.
Each of my batteries has a 100 amp BMS. The class T fuse is rated at 300 amps but is connected to the positive post of the battery with 12” of 2 gauge welding cable and the fuse holder is screwed to a steel plate on the shelf. The output of the class T feeds 2 gauge cable to a 100 amp midnight panel mounted breaker. The overload on the BMS is very fast and the class T is also a fast acting fuse. The 100 amp breakers are for convenience. I’m thinking I need to replace the class T’s with something smaller. Maybe 200 amp.

This is a reminder that as hard as we try to think of every possible scenario, Murphy never sleeps. I have done all I can and have a smoke detector directly above the battery rack.
 
Looking back on some photos you had in a previous Thread that had the fuse blocks as well as some of the wiring arrangement. I have to question if an arcing fuse caused the fire. Unfortunately there is insufficient images of your completed system and also the fire destroyed setup to have me concur with the fire inspector as to cause.
 
I sympathize with you. Your build looked to be a professional build looking at your previous post.

When fuses blow, then there is a root cause for the fuse to blow as I found out with my 93 Dodge Ram truck when one of the fusible links blew and the mechanic changed out the link without determining the root cause and it blew again which left me stranded in a very precarious situation.

I know this is hard for you but for all of us in this forum that have their family at risk, the more that we can find out about this tragic loss the safer we will all fill. I have my 110kwhr LFP pack in the cellar of my home. If that caught on fire, then the whole house would go.

I have my Cells divided into two parts with two class t 200 amp fuses to protect the Cells. There are 128 -280 amp Cells. I did not put my Cells in a metal enclosure or compress them. They are on a nice piece of wood. This has really got me thinking about what I can do to protect myself further.

I am thinking about maybe fire blankets or some sort of a fire alarm that can be heard while sleeping two floors above the cellar.

Any suggestions would be appreciated. The simpler the better.
Smoke detectors can work simultaneously these days, i.e the one in the basement goes off and all the others in the house also trigger.

Biggest issue I've seen is the shelves being made of some thin wood or fiber material and collapsing
 
Anyone installing mega fuses in a home system needs to realize they only protect from equipment overloads.
Class T fuses or similar high AIC interrupt are needed to protect from a short circuit.
Shorts can occur at any time with no warning.
Shielding from contact is needed between polarities.
All battery cabling needs to be securely mounted on non conductive surfaces.

Another fire with high capacity batteries. We ALL need to strive to be sure and advise others and ourselves of safety from short circuits and have high AIC interrupt capable fusing in place.
 
Smoke detectors can work simultaneously these days, i.e the one in the basement goes off and all the others in the house also trigger.

Biggest issue I've seen is the shelves being made of some thin wood or fiber material and collapsing
I have a set of 3 smoke detectors that are linked and if one trips, they all go off and announce which one tripped. Agree that wood shelves aren’t ideal here.
 
Also wanna add that we had 6 nest protects in the house, and none gave alarm but after 20 minutes when the house was full of smoke. My son discovered a meter of smoke against the ceiling and woke everyone up. If he hadnt wake up, there would have been 4 funerals this week.
 
Also wanna add that we had 6 nest protects in the house, and none gave alarm but after 20 minutes when the house was full of smoke. My son discovered a meter of smoke against the ceiling and woke everyone up. If he hadnt wake up, there would have been 4 funerals this week.
I think there are heat detectors that can be used in conjunction with smoke (particulate) detectors. They may see the heat flare from the arcing to give you advanced notice, or set up automation to trigger your battery disconnects/shunts.
 
I forget the correct terminology, but there was a mention recently of a better type of smoke detector. Not the cheapo $15 deal from Kitty that Home Depot sells. Perhaps it was an ionizing smoke detector?
 
Want to add that in my system i followed all fuse and wire specifications as indicated in the victron manuals.
This is something I have wondered about for quite a while. They support Megafuses in all their gear and sell 48B versions of Megafuses, but they never really address the AIC question. Several months back I had the chance to talk to a Victron 'ambassador' about a system and he was recommending a Cass-T.... which I found 'interesting' given this is not documented by Victron. When I pressed him on it he said he always uses a T class when more than one LiFePo4 battery is in parallel. He also claimed the ABYC was going to change their recommendation to more along the lines of what he is doing, but I don't know if that has happened.
 
@Jejochen So sorry for your loss but thankfully your and your family are safe.

Class T fuses or similar high AIC interrupt are needed to protect from a short circuit.
Shorts can occur at any time with no warning.
I'd add that Class T fuses are rated to open safely at these high AIC's without risk of causing other damage (exploding) or failing in such a way that they don't remain open. I can't readily find a reference but I've often heard it's possible for a fuse to fail in such a way that it doesn't open.
 
One tool that can come in handy to help prevent fires is a non contact thermometer. You should periodically run checks around your Inverter setup and batteries for hot spots.
View attachment 212063

Even better would taking the system to 100% of it's rating and checking voltage drop across every single connection. No need to wait for heat to build up or risk false readings from shiny terminals that don't like their temperature took.
 

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